1. Field of the Invention
The invention relates generally to battery-containing portable power systems and, more particularly, to battery-containing portable power systems for charging battery-powered portable devices.
2. Description of the Prior Art
Rechargeable battery-powered portable devices such as cellular telephones have, since their inception, been provided with proprietary adapters to provide power to their on-board rechargeable batteries. There is no standardization in the connectors between manufacturers or even devices of the same manufacturer, nor in the voltage and current required as input for these devices, as competition has led device manufacturers to produce proprietary connectors to prevent others from benefiting from their devices by selling adapters and to prevent consumers from easily switching from one device to another. This lack of standardization requires the consumer to carry more than one adapter if they are interested in charging portable devices from different manufacturers.
Adapters exist for connecting a rechargeable battery-powered device to some sort of auxiliary power, such as USB ports on computers, which may be connected to a cell phone, a personal digital assistant, or another device. These adapters, however, maintain a constant output voltage and do not take into account the voltage of the on-board battery of the cell phone or PDA, which is lower when it is nearly empty and higher as it nears full charge. Without accounting for this, the current may be too high for absorption by the battery and the excess current and power will be inefficiently lost in the form of heat. In any event, these adapters do not contain batteries and therefore they are not portable and are reliant on the presence of a wall electrical socket, a car electrical socket, a computer with a USB port or a USB/AC adapter which connects to a typical electrical wall socket and contains a USB port to which devices may be connected.
Portable power systems for portable devices which contain batteries exist but the batteries used are generally of the disposable variety. Those that allow the use of rechargeable batteries merely discharge the batteries into the portable device at the batteries' maximum rate, and do not manage the output current and voltage to keep the battery in its optimal operating range for safety, efficiency and longevity, nor do they contain redundant protection for the battery.
It is clear to those skilled in the art that there has been a longstanding need for a charging system that is self-contained, compatible with the myriad portable devices in the marketplace and capable of using a standard power sources such as USB, which is also electrically efficient and is able to effectively manage its battery for safety and long life.